1. Field of the Invention
The present invention relates to an optical information recording medium, or more specifically, to an optical information recording medium on which label information is recorded.
2. Description of the Related Art
A digital versatile disk (DVD) having a storage capacity several times as large as a compact disk (CD) such as CD-R or CD-RW has been widely used in recent years as an information recording medium for recording images and voices of a movie, for example. Conventionally, such a DVD includes a surface (a printable layer) on which desired information or an image is printable with a printer or the like on a surface (a label surface) provided on the opposite side to an incident side of recording and reproducing light on a dummy substrate (see Patent Document 1). Moreover, there is a proposal for enhancing a commercial value of a DVD with an extended printable region in recent years by extending a printable layer on a label surface to a clamping area that is located on an inner peripheral side of a recording area (a wide label).
(Patent Document 1)
Japanese Unexamined Patent Publication No. 2004-199771 (see column 0017)
Incidentally, DVDs today include about 8 types of recordable DVDs depending on the standard and the recordable speed, which have pigment layers that contain organic coloring compounds. Moreover, including rewritable DVDs having phase change type recording layers, there are around 20 product types in aggregate.
However, a region for allowing image printing is extended to the clamping area close to a center hole in the case of the wide label DVD. Accordingly, a region for recording label information such as a manufacturer of the DVD or a product type previously recorded in the clamping area is substantially reduced. For this reason, DVD manufacturers try to record the label information as inconspicuously as possible for instance in a similar color to backgrounds of printable surfaces, so as not to affect images printed by users.
Under the circumstances, there is a problem that a user of a DVD can hardly distinguish the various types of DVD products and determine a proper DVD at the point of use.
Moreover, the clamping area around the center hole is known as a region on which stress is highly concentrated when fitting the DVD into a drive or detaching the DVD therefrom. For this reason, in the case of the DVD formed by attaching a substrate having a recording and reproducing region to a dummy substrate has a risk of breakage attributable to deterioration in adhesion of the clamping area.